Modern, high performance watercraft frequently include buoyant outboard collar assemblies or stabilizers that mount onto the watercraft side sheets. The stabilizers provide safety and performance advantages. The stabilizers are configured to remain above the waterline during high-speed straight-line runs, and to engage the water during high-speed turns to limit the amount of heeling in the turn. The stabilizers also provide emergency flotation during unexpected events, for example, to counter rogue waves or to overcome other events that could threaten to swamp the watercraft. Exemplary high performance watercraft are disclosed, for example, in U.S. Pat. No. 5,870,965, to Hansen, which is hereby incorporated by reference in its entirety.
Rigid hull inflatable boats (RHIB) are lightweight but high-performance watercraft, typically constructed with a rigid hull and flexible, inflatable tubes at the gunwale. The inflatable tubes or collar maintain buoyancy of the watercraft, even if a large volume of water shipped aboard. RHIBs are frequently used for workboats, military watercraft, and lifeboats, for example. An exemplary RHIB is disclosed in U.S. Pat. No. 6,223,677, to Hall et al., which is hereby incorporated by reference. An exemplary RHIB with a foam insert is disclosed in U.S. Pat. No. 6,105,532, to Eilert, which is hereby incorporated by reference in its entirety.
An additional advantage of inflatable (air-filled) stabilizers and collars for watercraft are that they are more comfortable and safer for sitting on, and the like, due to their inherent resiliency or compliance, and they are less likely to be damaged from low-speed bumps and collisions. However, if an inflatable stabilizer or collar is punctured, or otherwise loses its inflation, the safety benefits are lost as the watercraft will lose significant buoyancy. Loss of inflation of the stabilizer may subject the watercraft to sinking or capsizing. Another advantage to inflatable stabilizers is that they can usually be easily deflated, for example, to reduce the width of the watercraft to facilitate transporting the watercraft over highways, or the like, and can be re-inflated for use. However, it can be time consuming to fully inflate the stabilizer.
An advantage of foam core stabilizers and collars is that they are not subject to leakage, so the risk of losing buoyancy is avoided. However, foam core stabilizers are less comfortable to sit on, and do not have the same flexibility as inflatable collars in the event the collar impacts another object. Impacts to foam core stabilizers, including repetitive low-speed impacts, can damage the foam core, requiring expensive repair. The foam core of the stabilizer may also shrink over time due to forces applied to the foam core, for example, compression of the foam core by the bladder that encloses the foam core. Over time the foam core becomes “loose” in the bladder, causing the stabilizer to lose some of its buoyancy, and reducing the aesthetic appearance of the watercraft. Also, in conventional foam core stabilizers, the stabilizer cannot be deflated to reduce the width of the watercraft. Therefore, typically the foam core stabilizer must be completely removed if it is necessary to reduce the overall width of the watercraft (i.e., for transporting the watercraft).